首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2269篇
  免费   351篇
  国内免费   673篇
  2024年   5篇
  2023年   63篇
  2022年   86篇
  2021年   74篇
  2020年   151篇
  2019年   139篇
  2018年   132篇
  2017年   145篇
  2016年   173篇
  2015年   97篇
  2014年   150篇
  2013年   453篇
  2012年   134篇
  2011年   164篇
  2010年   91篇
  2009年   126篇
  2008年   120篇
  2007年   151篇
  2006年   135篇
  2005年   117篇
  2004年   67篇
  2003年   83篇
  2002年   67篇
  2001年   54篇
  2000年   47篇
  1999年   38篇
  1998年   33篇
  1997年   30篇
  1996年   19篇
  1995年   27篇
  1994年   28篇
  1993年   26篇
  1992年   18篇
  1991年   2篇
  1990年   2篇
  1989年   6篇
  1988年   2篇
  1987年   2篇
  1986年   2篇
  1985年   7篇
  1984年   1篇
  1983年   2篇
  1981年   1篇
  1980年   1篇
  1979年   7篇
  1978年   7篇
  1977年   4篇
  1976年   4篇
排序方式: 共有3293条查询结果,搜索用时 15 毫秒
261.
情绪记忆增强(Emotionally Enhanced Memory, EEM)效应受到刺激的唤醒度和效价的影响。Kensinger 等人提出依赖于唤醒的 EEM 效应与自动加工相联系,依赖于效价的 EEM 效应与控制加工相联系。然而现有研究并不能为这一假设提供充分的证据。本研究的三个实验采用学习--再认范式和 DA 范式(divided attention paradigm)相结合的方法,分别考察了在两种注意条件下依赖于唤醒和依赖于效价的EEM 效应在编码阶段的加工机制。结果发现,中性词、正性非唤醒词、负性非唤醒词在集中注意条件下的记忆再认成绩显著高于分散注意条件下的记忆再认成绩;正性唤醒词在集中注意条件下的记忆再认成绩也显著高于分散注意条件下的记忆再认成绩,但负性唤醒词的记忆再认成绩在两种注意条件下不存在显著差异。这表明依赖于效价的 EEM 效应与控制加工相联系,而依赖于唤醒的 EEM 效应并不总是与自动加工相联系,其加工还受到情绪效价的调节,对于负性刺激,依赖于唤醒的 EEM 效应与自动加工相联系;对于正性刺激,依赖于唤醒的EEM效应则与控制加工相联系。  相似文献   
262.
This study assessed the unique associations of risk perceptions and worry with attitudes about genetic testing for breast cancer susceptibility. Women (general practitioner clinic attenders, university students, and first-degree relatives of breast cancer survivors; N?=?303) read information about genetic testing and completed measures assessing perceived cancer risk, cancer worry, and genetic testing attitudes and beliefs. Worry was associated with greater interest in genetic testing, stronger beliefs that testing has detrimental emotional consequences, and positive beliefs about benefits of testing and risk-reducing surgeries. Perceived risk was unrelated to interest and associated with more skeptical beliefs about emotional consequences and benefits of testing and risk-reducing surgeries. At low worry levels, testing interest increased with more positive beliefs about testing benefits; at high worry levels, interest was high regardless of benefits beliefs. The findings support Leventhal's Common-Sense Model of self-regulation delineating interactive influences of risk-related cognitions and emotions on information processing and behavior.  相似文献   
263.
Abstract

Objective: Hereditary Haemorrhagic Telangiectasia (HHT) is a genetic condition causing frequent nose bleeds, skin lesions (telangiectasia) and arteriovenous malformations. Approximately, 50% of people experience life-threatening HHT symptoms including haemorrhages in the brain, lungs and liver. This study aimed to gain a qualitative understanding of the psychosocial impact of HHT over time. Design: Using a phenomenological framework, a rigorous narrative analysis was performed on 20 semi-structured interviews with individuals with HHT aged 20s–60s. Main outcome measures: Qualitative themes explaining life experiences prior to and following a clinical diagnosis of HHT. Results: Narratives highlighted four psychosocial themes: (i) the psychological impact of visible symptoms was significant and related to experiences of social stigma, (ii) individuals struggled to identify triggers of symptoms in order to reduce unpredictability, (iii) an illness identity was rejected by minimising HHT when talking about the present self, and by positive reframing as ‘lucky’ and (iv) self-advocacy was necessitated due to lack of expert coordinated care. Conclusion: HHT has a demanding impact on social, physical and psychological well-being. These findings have significant implications for health care, as narratives about interactions with health professionals often used the terms ‘frustrating’ and ‘not being heard’.  相似文献   
264.
Direct-to-consumer (DTC) genetic testing is an increasingly available option among individuals searching for information about their health risk factors and ancestry. This study is one of the first to examine predictors of interest in DTC genetic testing. Participants read one of the three types of information about DTC genetic testing (positive only, negative only or both) and reported perceptions of and intentions to pursue testing. The information which people read, their perceptions of the benefits of testing, their perceptions of the barriers to testing and anticipated regret predicted intentions to undergo testing. Interestingly, people who read both positive and negative information did not differ from people who read only negative information in their intentions to pursue testing. We discuss the implications of these findings for predicting interest in this relatively new type of genetic testing and for designing interventions to encourage (or discourage) testing.  相似文献   
265.
Health professionals do not inform their patients’ kin about BRCA1/2 test results or genetic testing without their written consent. Thus, the onus is on women attending genetic counselling to talk to relatives about the family history and their potential increased risk. This communication process within the family is largely unexplored and provides the focus of the present study. Fifteen healthy women attending a genetics clinic for predictive testing were interviewed prior to receiving their test result and again 6 months later. A grounded theory approach was used. Findings illustrate the dilemmas women faced in juggling social roles and expectations, which had an impact on communication within the family in the context of predictive genetic testing. Tensions between responsibilities towards themselves and others and their fulfilment of social roles had an impact on who women informed and on how they did so. These factors should be considered when assigning patients the role of information provider.  相似文献   
266.
Reading decoding requires the association of a visual input (the printed word) with a verbal output (the spoken word), and the learning of visual-phonological associations via repeated exposure occurs both explicitly (by instruction and training) and implicitly (by exposure to written material). However, a general ability to implicitly learn visual-phonological associations (or cross-modal bindings) in children with reading difficulties (RD) has not been deeply explored. The present paper examined this issue in two studies comparing groups of children with RD with matched groups of control children in a working memory binding task involving sequences of variable combinations of nonsense shapes and nonwords (odd trials), as well as fixed combinations (even trials). Stimuli presentation was followed by a recognition test in which the nonwords were given one at a time and the children were required to mouse click on their respective shapes. In Study 1, fixed bindings were presented in random sequences across even trials, and the recognition test presented the nonwords at random. In Study 2, fixed bindings were presented in the same order across even trials, and the recognition test presented the nonwords following the same sequence order. In both studies, a consistent and strong learning effect of fixed bindings was observed for the control groups, with significantly better performance than the groups with RD. Such results suggest that poor cross-modal binding learning is associated with reading difficulties. Implications for the study and treatment of dyslexia are discussed.  相似文献   
267.
A numerical model is proposed to simulate fracture induced by the coalescence of numerous microcracks, in which the condition for coalescence between two randomly nucleated microcracks is determined in terms of a load-sharing principle. The results of the simulation show that, as the number density of nucleated microcracks increases, stochastic coalescence first occurs followed by a small fluctuation, and finally a newly nucleated microcrack triggers a cascade coalescence of microcracks resulting in catastrophic failure. The fracture profiles exhibit self-affine fractal characteristics with a universal roughness exponent, but the critical damage threshold is sensitive to details of the model. The spatiotemporal distribution of nucleated microcracks in the vicinity of critical failure follows a power-law behaviour, which implies that the microcrack system may evolve to a critical state.  相似文献   
268.
We report on the effect of cooling rate on the size-dependent atomic ordering of CoPt nanoparticles using aberration corrected high-resolution transmission electron microscopy. It was found that cooling rate plays a crucial role in promoting atomic ordering during the cooling process after annealing. Nanoparticles of ≈3?nm in diameter show the A1-disordered phase after annealing at 873?K for 1?h followed by rapid cooling (110?K/min), while the L10-ordered phase is obtained when the cooling rate is slow (1.5?K/min). The disordered phase is also obtained by rapid cooling after annealing at 973?K for 1?h. These results unambiguously indicate that the order–disorder transformation temperature is reduced to a temperature at least lower than 873?K for CoPt nanoparticles smaller than 3?nm in diameter. The slow cooling process promotes the atomic ordering, which resulted in an enhancement of magnetic coercivity as high as 2200?Oe. This study demonstrates that hard magnetic properties of the CoPt nanoparticles can be improved by controlling the cooling rate after heat treatments.  相似文献   
269.

In this letter, the dislocation patterns on the common primary slip plane in a fatigued \[1-34]-\[182-7] copper bicrystal with a Sigma=19b grain boundary (GB) have been investigated using the electron channelling contrast technique in a scanning electron microscope. The results show that the two-phase dislocation structure, such as veins and persistent slip band (PSB) walls, embedded within veins, can be clearly seen on the common primary slip plane. In particular, the interactions of PSBs with the GB are clearly revealed. It is found that there are three kinds of interaction mode between the GB and the dislocations during cyclic deformation, and those are discussed. It is suggested that the dislocations carried by PSBs cannot transfer through the GB continuously even though the bicrystal has a common primary slip plane and its surface slip bands are continuous across the GB.  相似文献   
270.
The specific heat and magnetocaloric effect (MCE) of A-site ordered PrBaMn2O6 manganite have been studied. The anomalies caused by the ferromagnetic (FM) and antiferromagnetic (AFM) phase transitions are revealed in the specific heat curve. Direct and inverse MCE are observed at the Curie and Néel points correspondingly. A value of the inverse MCE in the heating run is smaller than in the cooling regime. We attribute this effect to the competition between FM and AFM interactions. A significant advantage of PrBaMn2O6 as a magnetocaloric material is an MCE spanning a broad range of temperature with a maximum at room temperature.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号